1. Field of the Invention
The present invention relates to liquid cleansing compositions suitable for topical application for cleansing the human body, such as the skin and hair. In particular, it relates to a stable, substantially isotropic and finely dispersed oil free personal cleansing composition that is able to suspend appreciable levels of insoluble ingredients and produce copious lather.
2. Background of the Art
Commercially available liquid personal cleansing compositions such as shower gels, facial and hand cleansers are generally applied to cleanse the skin. The lather such products produce is an important sign to the user that the product is working while providing pleasant sensory effects. Another important attribute of the product to the user is the visual appearance which can help communicate various benefits through the addition of particles such as opacifiers, mica, beads, oils etc. that are visible to the user.
Isotropic liquid cleansers are known that have hydrophobic emollient oils. U.S. Pat. No. 6,001,344 issued on Dec. 14, 1999 to Villa et al. discloses an isotropic cleansing composition having large oil droplets in the 1 to 500 micron range average diameter.
U.S. Pat. Nos. 5,854,293 and 6,066,608 issued on Dec. 29, 1998 and on May 23, 2000 to Glenn Jr. respectively disclose a moisturizing liquid personal cleansing emulsion with at least 10% of its lipophilic skin moisturizing agent droplets having a diameter of greater than 200 microns with an analytical range of detection of up to 1000 microns.
U.S. Pat. No. 5,965,500 issued on Oct. 12, 1999 to Puvvada discloses a stable, isotropic liquid cleansing composition containing high levels of emollients equal to or in excess of the surfactant level. The composition further contains C2-C24 carboxylic acids and/or cationic polymers in a preferred embodiment.
U.S. Pat. No. 5,661,189 issued on Aug. 26, 1997 to Grieveson et al. discloses an isotropic, aqueous liquid cleansing and moisturizing composition with a thickened benefit agent having a weight average particle size in the range of 50 to 500 microns and an optional structuring agent selected from clays, carboxylic acids and derivatives thereof, cross-linked polyacrylates, polyvinylpyrrolidone, natural gums, polysaccharide derivatives, polyols, polyol esters and inorganic salts.
U.S. Pat. No. 7,098,180 issued on Aug. 29, 2006 to Ganopolsky et al. discloses an isotropic cleansing composition containing anionic and amphoteric surfactants, and a hydrophobically modified crosslinked, anionic acrylic copolymer.
U.S. Patent Publication No. 2004/0121925 published on Jun. 24, 2004 to Harmalker discloses a stable isotropic cleansing composition containing anionic and amphoteric surfactants, xanthan and guar gum thickeners, and dispersed phase suspended particles of conditioning agents in the 200-2500 micron diameter range and with a clarity of less than or equal to 20 NTU of the continuous phase absent the particles. The particles consist of gums, gelatins or the like and may contain oil(s) within the particles.
U.S. Pat. No. 7,084,104 issued on Aug. 1, 2006 to Martin et al. discloses an isotropic cleansing composition containing anionic and amphoteric surfactants, a hydrophobically modified crosslinked, anionic acrylic copolymer thickener, volatile silicone conditioners and humectants.
U.S. Pat. No. 6,191,083 issued on Feb. 20, 2001 to Brooks, et al. discloses cleansing compositions with thickening systems that comprise an associative polymer and a polar oil.
U.S. Pat. No. 5,869,070 issued on Feb. 9, 1999 to Dixon et al. discloses cleansing compositions stabilized by specific gel-forming polymers containing a lipid moisturizing agent.
U.S. Patent Publication No. 2007161524 published on Jul. 12, 2007 to Counradi, Katrin; et al. discloses foaming cleansing solutions comprising anionic surfactants, gel-forming acrylate thickeners and a mixture of ethoxylated mono, di, and triglycerides of C8-C22 carboxylic acids.
As discussed in these and other prior art references, it is known to use carboxylic acids and acrylate copolymers either separately or together to structure anionic surfactant cleansing compositions. However it was surprisingly discovered that specific carboxylic acids and specific crosslinked acrylates form a synergistic combination to affect zero shear viscosity at 25 C substantially beyond what would be expected from the simple combination of the two. Moreover, unexpected copious and creamy lather creation of the inventive compositions was seen to be a side benefit. In addition, the enhanced suspending ability at increased zero shear viscosity levels for insoluble components such as beads, particles and large oil droplets above 500 or 1000 microns average diameter was another synergistic benefit.